1882.1 



403 



[Genth^ 



Their analysis proved them to be allanite. Sp. gr. := 3.005. As the quan- 

 tity for examination was very small the cerium oxides were not sepa- 

 rated. 



For comparison I give the analysis of a variety of allanite from the 

 Mica Mine of Balsam Gap in Buncombe Co., N. C, where it occurs in jet 

 black or brownish-black slender crystals, sometimes Irom six to twelve 

 inches in length (Minerals, &c. of North Carolina, Raleigh, 1881). Spec, 

 srav. = 3.400.— 



SiOa 



AI2O3 



FeA 



FeO 



MnO 



CcOg ; 



(DiLa)203 ' 



Y2O3 



MgO 



CaO 



Na^O 



Ignition 



5.70 



99.65 



XI. Niccolite from Colorado. 



In the American Journal of Science [3] xxiii, 380, Mr. Malvern W. 

 lies mentions the occurrence of smaltite near Gothic, Gunnison Co., Colo- 

 rado, and gives an analysis of the same. He states that the Gem and 

 other mines near Silver Cliff, Colorado, contain a number of nickeliferous 

 minerals and a small amount of cobalt. 



About two years ago I received fragments of niccolite from Colorado 

 from some of mj^ students, and about a year ago Mr. Henry A. Vezin sent 

 me a specimen from Silver Cliff, which was pure enough for examination. 



It occurs in rounded or nodular masses disseminated through a granular 

 limestone, which has the appearance of dolomite, but contains only a very 

 small percentage of magnesia. In dissolving the limestone, the niccolite 

 remains in small irregular masses, partly made up *by globular and 

 botryoidal aggregations with a crystalline black surface, showing the 

 crystals of niccolite to be exceedingly small and indistinct ; I have not 

 seen any in which the form could be made out. It has a very pale copper- 

 red color with a grayish tint. Sp. gr. =: 7.314. 



Associated with it in druses of the limestone are globular crystalline 

 groups of an apple-green mineral, which is probably an arseniate of nickel 

 but which has not the appearance or annabergite. 



PROC. AMER. PHILOS. SOC. XX. 112. 3y. PRINTED NOV. 8, 1882. 



